From: Alexei Starovoitov <ast@xxxxxxxxxx>
Add various tests to check helper access into ptr_to_btf_id.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
.../selftests/bpf/progs/task_kfunc_failure.c | 36 +++++++++++++++++++
.../selftests/bpf/progs/task_kfunc_success.c | 4 +++
2 files changed, 40 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
index 002c7f69e47f..27994d6b2914 100644
--- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
+++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
@@ -301,3 +301,39 @@ int BPF_PROG(task_kfunc_from_lsm_task_free, struct task_struct *task)
bpf_task_release(acquired);
return 0;
}
+
+SEC("tp_btf/task_newtask")
+__failure __msg("access beyond the end of member comm")
+int BPF_PROG(task_access_comm1, struct task_struct *task, u64 clone_flags)
+{
+ bpf_strncmp(task->comm, 17, "foo");
+ return 0;
+}
+
+SEC("tp_btf/task_newtask")
+__failure __msg("access beyond the end of member comm")
+int BPF_PROG(task_access_comm2, struct task_struct *task, u64 clone_flags)
+{
+ bpf_strncmp(task->comm + 1, 16, "foo");
+ return 0;
+}
+
+SEC("tp_btf/task_newtask")
+__failure __msg("write into memory")
+int BPF_PROG(task_access_comm3, struct task_struct *task, u64 clone_flags)
+{
+ bpf_probe_read_kernel(task->comm, 16, task->comm);
+ return 0;
+}
+
+SEC("fentry/__set_task_comm")
+__failure __msg("R1 type=ptr_ expected")
+int BPF_PROG(task_access_comm4, struct task_struct *task, const char *buf, bool exec)
+{
+ /*
+ * task->comm is a legacy ptr_to_btf_id. The verifier cannot guarantee
+ * its safety. Hence it cannot be accessed with normal load insns.
+ */
+ bpf_strncmp(task->comm, 16, "foo");
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c
index aebc4bb14e7d..4f61596b0242 100644
--- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c
+++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c
@@ -207,6 +207,10 @@ int BPF_PROG(test_task_from_pid_invalid, struct task_struct *task, u64 clone_fla
if (!is_test_kfunc_task())
return 0;
+ bpf_strncmp(task->comm, 12, "foo");
+ bpf_strncmp(task->comm, 16, "foo");
+ bpf_strncmp(&task->comm[8], 4, "foo");
+
if (is_pid_lookup_valid(-1)) {
err = 1;
return 0;
--
2.34.1
